Low temperature photoluminescence studies on sputter deposited cadmium sulphide/cadmium telluride heterojunctions and solar cells

Device quality CdS/CdTe heterostructures and completed solar cells (~12% efficient) have been studied using low-temperature photoluminescence (PL). The PL was studied as a function of temperature (82-295 K) and laser excitation power (0.02-2 mW). The CdS/CdTe junctions were grown on transparent conducting oxide covered soda lime glass using rf-sputter deposition. It was found that the luminescence shifts from being dominated by sub-gap defect mediated emission at lower excitation powers to near band edge excitonic emission at higher excitation powers. The effect of copper (Cu) used in making back contacts was studied in connection with the CdS/CdTe junction PL. It was found that the presence of Cu suppresses the sub-band gap PL emissions. This effect is thought to be either due to Cu occupying cadmium vacancies (VCd) or forming acceptor complexes with them. This points to a potential role of Cu in plugging sub-band gap recombination routes and hence increasing charge separation ability of the device. An energy band diagram is presented indicating various observed transitions and their possible origins.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Materials Science & Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Tuteja, Mohit

Contributors dc:contributor

• Rockett, Angus A.

• Photoluminescence
• Defect
• Cadmium Telluride (CdTe)
• Cadmium Sulfide (CdS)
• Solar Cells

Statement dc:rights

• Copyright 2014 Mohit Tuteja

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/50593

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/50593